A variety of analyses, including fluorescence in situ hybridization (FISH), quantitative PCR (qPCR) and array CGH (aCGH), have been performed on a series of chordomas from 181 patients. Twelve of 181 (7%) tumours displayed amplification of the T locus and an additional two cases showed focal amplification; 70/181 (39%) tumours were polysomic for chromosome 6, and 8/181 (4.5%) primary tumours showed a minor allelic gain of T as assessed by FISH. No germline alteration of the T locus was identified in non-neoplastic tissue from 40 patients. Copy number gain of T was seen in a similar percentage of sacrococcygeal, mobile spine and base of skull tumours. Knockdown of T in the cell line, U-CH1, which showed polysomy of chromosome 6 involving 6q27, resulted in a marked decrease in cell proliferation and morphological features consistent with a senescence-like phenotype. The U-CH1 cell line was validated as representing chordoma by the generation of xenografts, which showed typical chordoma morphology and immunohistochemistry in the NOD/SCID/interleukin 2 receptor [IL2r]gammanull mouse model. In conclusion, chromosomal aberrations resulting in gain of the T locus are common in sporadic chordomas and expression of this gene is critical for proliferation of chordoma cells in vitro.

Chordoma is a rare malignant bone tumour with a poor prognosis and limited therapeutic options. We undertook a focused compound screen (FCS) against 1097 compounds on three well‐characterized chordoma cell lines; 154 compounds were selected from the single concentration screen (1 µm), based on their growth‐inhibitory effect. Their half‐maximal effective concentration (EC50) values were determined in chordoma cells and normal fibroblasts. Twenty‐seven of these compounds displayed chordoma selective cell kill and 21/27 (78%) were found to be EGFR/ERBB family inhibitors. EGFR inhibitors in clinical development were then studied on an extended cell line panel of seven chordoma cell lines, four of which were sensitive to EGFR inhibition. Sapitinib (AstraZeneca) emerged as the lead compound, followed by gefitinib (AstraZeneca) and erlotinib (Roche/Genentech). The compounds were shown to induce apoptosis in the sensitive cell lines and suppressed phospho‐EGFR and its downstream pathways in a dose‐dependent manner. Analysis of substituent patterns suggested that EGFR‐inhibitors with small aniline substituents in the 4‐position of the quinazoline ring were more effective than inhibitors with large substituents in that position. Sapitinib showed significantly reduced tumour growth in two xenograft mouse models (U‐CH1 xenograft and a patient‐derived xenograft, SF8894). One of the resistant cell lines (U‐CH2) was shown to express high levels of phospho‐MET, a known bypass signalling pathway to EGFR. Neither amplifications (EGFR, ERBB2, MET) nor mutations in EGFR, ERBB2, ERBB4, PIK3CA, BRAF, NRAS, KRAS, PTEN, MET or other cancer gene hotspots were detected in the cell lines. Our findings are consistent with the reported (p‐)EGFR expression in the majority of clinical samples, and provide evidence for exploring the efficacy of EGFR inhibitors in the treatment of patients with chordoma and studying possible resistance mechanisms to these compounds in vitro and in vivo. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Sclerosing epithelioid fibrosarcoma (SEF) is a highly aggressive soft tissue sarcoma closely related to low-grade fibromyxoid sarcoma (LGFMS). Some tumors display morphologic characteristics of both SEF and LGFMS, hence they are known as hybrid SEF/LGFMS. Despite the overlap of gene fusion variants between these two tumor types, SEF is much more aggressive. The current study aimed to further characterize SEF and hybrid SEF/LGFMS genetically to better understand the role of the characteristic fusion genes and possible additional genetic alterations in tumorigenesis. We performed whole-exome sequencing, SNP array analysis, RNA sequencing (RNA-seq), global gene expression analyses, and/or IHC on a series of 13 SEFs and 6 hybrid SEF/LGFMS. We also expressed the and fusion genes conditionally in a fibroblast cell line; these cells were subsequently analyzed by RNA-seq, and expression of the CD24 protein was assessed by FACS analysis. The SNP array analysis detected a large number of structural aberrations in SEF and SEF/LGFMS, many of which were recurrent, notably microdeletions. RNA-seq identified and as alternative fusion genes in one SEF each. was strongly upregulated, presumably a direct target of the fusion proteins. This was further confirmed by the gene expression analysis and FACS analysis on Tet-On 3G cells expressing Although gene fusions are the primary tumorigenic events in both SEF and LGFMS, additional genomic changes explain the differences in aggressiveness and clinical outcome between the two types. CD24 and DMD constitute potential therapeutic targets..

The mechanisms of metal release from the articulation at the head cup bearing and the tapered junctions of orthopaedic hip implants are known to differ and the debris generated varies in size, shape and volume. Significantly less metal is lost from the taper junction between Cobalt-Chromium-Molybdenum (CoCrMo) and Titanium (Ti) components (fretting-corrosion dominant mechanism), when compared to the CoCrMo bearing surfaces (wear-corrosion dominant mechanism). Corrosion particles from the taper junction can lead to Adverse Reactions to Metal Debris (ARMD) similar to those seen with CoCrMo bearings. We used synchrotron methods to understand the modes underlying clinically significant tissue reactions to Co, Cr and Ti by analysing viable peri-prosthetic tissue. Cr was present as Cr2O3 in the corroded group in addition to CrPO4 found in the metal-on-metal (MoM) group. Interestingly, Ti was present as TiO2 in an amorphous rather than rutile or anatase physical form. The metal species were co-localized in the same micron-scale particles as result of corrosion processes and in one cell type, the phagocytes. This work gives new insights into the degradation products from metal devices as well as guidance for toxicological studies in humans.

In the cranio-facial skeleton, a heterogeneous group of well characterized fibro-osseous lesions can be distinguished. Whereas fibrous dysplasia can affect any skeletal bone, ossifying fibroma and cemento-osseous dysplasia exclusively develop in the cranio-facial region, with most subtypes restricted to the tooth bearing areas of the jaws. Herein we present a series of 20 fibro-osseous lesions that developed mostly in the frontal bone and in the mandible, presenting as expansile intramedullary tumors with a unique histologic appearance and an indolent clinical course. We provide evidence that these tumors are distinct from the categories included in the WHO classification and are therefore currently unclassifiable. The definition of cemento-ossifying fibroma as an odontogenic neoplasm developing only in close proximity to teeth should be re-considered and incorporate also extragnathic lesions as shown here.